The purpose of this proposal is to provide adequate staff and laboratory resources specifically designed for investigating the naturally occurring diseases of animals used in research at the Johns Hopkins University and affiliated institutions. Particular emphasis is placed on providing diagnostic support to outbreaks of naturally occurring animal disease in the various animal colonies and to the development and implementation of procedures to control such outbreaks. The support of preventive medical programs to minimize introduction of diseased animals into the colonies is an important aspect of the program. The investigation of naturally occurring diseases is carried out in such a manner as to describe, in detail, the problems, their etiology and importance to Laboratory Animal Medicine and, as appropriate, as animal models for the study of human disorders. The elucidation of those diseases which may interfere with the valid interpretation of investigative procedures is also emphasized. Necropsies are carefully carried out on animals submitted for examination, gross and microscopic slides prepared and pertinent information entered into a computerized data retrieval system. Clinical pathology and microbiology laboratories, including virology, have been developed to support the purposes of this application. Additionally, these studies and the information and material so derived provide excellent training, teaching and research resources for postdoctoral training programs in both Laboratory Animal Medicine and Laboratory Animal (Comparative) Pathology.